Catheter introducer systems are often introduced into blood vessels and organs for intraluminal diagnostics, treatment and delivery of medical devices and structures. The type of catheter introducer system utilized depends on the medical procedure performed, the route in the body taken, and individual patient anatomy, among other factors. A tortuous blood vessel refers to a blood vessel that is particularly difficult to advance an intraluminal device through, such as a catheter introducer system, usually due to tight and/or reverse bends defined by the path of the blood vessel. An example of a procedure that traverses particularly tortuous blood vessels is where transvenous access to the main pulmonary artery is desired from the femoral vein.
Dilators are used to expand narrowed blood vessels and/or to enable the introduction of a larger diameter intraluminal device. Dilators are limited in their ability to navigate tortuous bends. Where a guidewire may be able to traverse a particular bend, a dilator and sheath system may not be able to track over the guidewire and traverse the particular bend. Prior art dilator and sheath systems are designed to be advanced as a single unit. This method of operation, combined with dilators not substantially longer than their associated sheath, results in an abrupt transition in bending stiffness from the guidewire to the dilator and sheath system. The guidewire may be deflected out of position by the dilator and sheath instead of the guidewire presenting itself as a stable track path. Further, the tip of the sheath may abut and damage the blood vessel. What is needed in the art is a dilator system capable of traversing tortuous blood vessels, and a catheter introducer system including the dilator system that is capable of traversing tortuous blood vessels.